We use substitution to calculate the values. For example y = 2x + 1 The y value is always '2 lots' of the x value plus 1. We replace the value of x for different numbers and record the resulting y ...

GCSE Edexcel Straight line graphs - Edexcel y = mx + c Graphs show the relationship between two variables and are often seen in newspapers and the media. People who work in professions involving ...